I have a problem with my Acer palmatum getting brown edges on the leaves,
and the leaves beginning to curl up. I have just read on the net that it
probably has to do with too much intense sunlight during the middle of the
day...
I live in sub-tropical Australia

Acer palmatum is a temperate understory tree. It should get partial shade, with
some sort of windbreak. If you can get hold of Dyna-Gro Pro-TeKt, which is
Potassium silicate, I have found it very helpful. Use it once a month.
Iris,
Central NY, Zone 5a, Sunset Zone 40
"If we see light at the end of the tunnel, It's the light of the oncoming
train."
Robert Lowell (1917-1977)